Field of the Invention
The invention relates to a flame sensor and, more particularly, to a flame sensor for sensing characteristics of a flame in a high temperature combustion chamber.
Discussion of Prior Art
Within an oil or gas fueled turbine with a combustion chamber, fuel is fed into the combustion chamber within which an ignition flame is present. If the flame becomes extinguished, commonly referred to as a flame-out condition, it is undesirable for fuel to continue to be fed into the hot combustion chamber without appropriate ignition. Consequently, if the ignition flame is extinguished within the combustion chamber, the fuel feed into the combustion chamber should be quickly terminated and thus limit un-combusted fuel build up.
A flame sensor is generally used for detecting the presence or absence of an ignition flame within a combustion chamber of a gas turbine. Also, flame sensing electronics are commonly associated with the flame sensor within the turbine arrangement. The flame sensing electronics may be temperature sensitive. Due to the relatively hot temperatures in and near the combustion chamber, water cooling is often used to cool the temperature sensitive flame sensing electronics. However, water may occasionally leak and, if sprayed on the relatively hot housing of the turbine, may cause the turbine housing to contract, causing damage to the turbine. Accordingly, it would be useful to provide a flame sensor that eliminates the need for water cooling and which the circuitry is electrically remote from the relatively high temperature near the combustion process/chamber.
It is to be appreciated that there may be a need for operation of a flame sensor within a setting in which some components experience a relatively high temperature, such as a temperature at or greater than 200° C. (392° F.) and possibly such as at temperature at or greater than 250° C. (482° F.). As such there is a need for continued improvements concerning flame sensors.